The invention relates to a device for stacking flat, flexible postal items in a stacking compartment.
Such stacking compartments are for example components of sorting compartment lines in postal item sorting installations. Postal items are distributed according to the destination addresses into the assigned stacking compartments via a transport path with points-type switches. To achieve a high throughput of the sorting installations, the distances between the postal items (item gaps) are selected to be as small as possible. If different types of items (e.g. thin, unstable, tall postal items, open magazines) are to be stacked they are to be put into a state whereby they pass on a largely unsupported path between the last clamping point of the transport path and the stacking roller without the open postal items being blown open by the wind caused by their movement and thereby being folded or damaged during stacking. Furthermore the tall, unstable postal items are to be stabilized so that they do not collide with the postal items already stacked.
A stacking device is described in the prior art (EP 0 127 067 A1), which possesses a so-called beaded roller as the deflection roller of the shorter covered belt. This beaded roller, which is longer than the width of the covered belt, has a bead at each end. Since the moving belt of the covered belt system presses the postal item in its center against the beaded roller and the outer parts of the item are in contact with the beads in this case, a flexible item is bent and thus stabilized, so that it does not deform when routed on one side into the stacking compartment. Thus a lengthwise reinforcement for stabilization can be only be achieved for short unstable items. Tall unstable and open postal items cannot be stacked securely and without problems using this method.